Request For Comments: 1156 Hughes LAN Systems
Obsoletes: RFC1066 M. Rose
Performance Systems International
May 1990
Management Information Base for Network Management
of TCP/IP-based internets
Table of Contents
1. Status of this Memo ................................... 1
2. IAB Policy Statement .................................. 2
3. Introduction .......................................... 2
4. Objects ............................................... 6
4.1 Object Groups ........................................ 6
4.2 Format of Definitions ................................ 7
5. Object Definitions .................................... 8
5.1 The System Group ..................................... 9
5.2 The Interfaces Group ................................. 11
5.2.1 The Interfaces Table ............................... 11
5.3 The Address Translation Group ........................ 23
5.4 The IP Group ......................................... 26
5.4.1 The IP Address Table ............................... 34
5.4.2 The IP Routing Table ............................... 36
5.5 The ICMP Group ....................................... 43
5.6 The TCP Group ........................................ 53
5.7 The UDP Group ........................................ 62
5.8 The EGP Group ........................................ 64
5.8.1 The EGP Neighbor Table ............................. 65
6. Definitions ........................................... 68
7. Acknowledgements ...................................... 89
8. References ............................................ 90
9. Security Considerations................................ 91
10. Authors' Addresses.................................... 91
1. Status of this Memo
This RFCis a re-release of RFC1066, with a changed "Status of this
Memo", "IAB Policy Statement", and "Introduction" sections plus a few
minor typographical corrections. The technical content of the
document is unchanged from RFC1066.
This memo provides the initial version of the Management Information
Base (MIB) for use with network management protocols in TCP/IP-based
internets in the short-term. In particular, together with its
companion memos which describe the structure of management
information along with the initial network management protocol, these
documents provide a simple, workable architecture and system for
managing TCP/IP-based internets and in particular the Internet.
This memo specifies a Standard Protocol for the Internet community.
TCP/IP implementations in the Internet which are network manageable
are expected to adopt and implement this specification.
The Internet Activities Board recommends that all IP and TCP
implementations be network manageable. This implies implementation
of the Internet MIB (RFC-1156) and at least one of the two
recommended management protocols SNMP (RFC-1157) or CMOT (RFC-1095).
It should be noted that, at this time, SNMP is a full Internet
standard and CMOT is a draft standard. See also the Host and Gateway
Requirements RFCs for more specific information on the applicability
of this standard.
Please refer to the latest edition of the "IAB Official Protocol
Standards" RFCfor current information on the state and status of
standard Internet protocols.
Distribution of this memo is unlimited.
2. IAB Policy Statement
This MIB specification is the first edition of an evolving document
defining variables needed for monitoring and control of various
components of the Internet. Not all groups of defined variables are
mandatory for all Internet components.
For example, the EGP group is mandatory for gateways using EGP but
not for hosts which should not be running EGP. Similarly, the TCP
group is mandatory for hosts running TCP but not for gateways which
aren't running it. What IS mandatory, however, is that all variables
of a group be supported if any element of the group is supported.
It is expected that additional MIB groups and variables will be
defined over time to accommodate the monitoring and control needs of
new or changing components of the Internet. The responsible working
group(s) will continue to refine this specification.
3. Introduction
As reported in RFC1052, IAB Recommendations for the Development of
Internet Network Management Standards [1], the Internet Activities
Board has directed the Internet Engineering Task Force (IETF) to
create two new working groups in the area of network management. One
group was charged with the further specification and definition of
elements to be included in the Management Information Base. The
other was charged with defining the modifications to the Simple
Network Management Protocol (SNMP) to accommodate the short-term
needs of the network vendor and operator communities. In the long-
term, the use of the OSI network management framework was to be
examined using the ISO CMIS/CMIP [2,3] framework as a basis. Two
documents were produced to define the management information: RFC
1065, which defined the Structure of Management Information (SMI)
[4], and RFC1066, which defined the Management Information Base
(MIB) [5]. Both of these documents were designed so as to be
compatible with both the SNMP and the OSI network management
framework.
This strategy was quite successful in the short-term: Internet-based
network management technology was fielded, by both the research and
commercial communities, within a few months. As a result of this,
portions of the Internet community became network manageable in a
timely fashion.
As reported in RFC1109, Report of the Second Ad Hoc Network
Management Review Group [6], the requirements of the SNMP and the OSI
network management frameworks were more different than anticipated.
As such, the requirement for compatibility between the SMI/MIB and
both frameworks was suspended.
The IAB has designated the SNMP, SMI, and the initial Internet MIB to
be full "Standard Protocols" with "Recommended" status. By this
action, the IAB recommends that all IP and TCP implementations be
network manageable and that the implementations that are network
manageable are expected to adopt and implement the SMI, MIB, and
SNMP.
As such, the current network management framework for TCP/IP- based
internets consists of: Structure and Identification of Management
Information for TCP/IP-based Internets, which describes how managed
objects contained in the MIB are defined as set forth in RFC1155
[7]; Management Information Base for Network Management of TCP/IP-
based Internets, which describes the managed objects contained in the
MIB as set forth in this memo; and, the Simple Network Management
Protocol, which defines the protocol used to manage these objects, as
set forth in RFC1157 [8].
The IAB also urged the working groups to be "extremely sensitive to
the need to keep SNMP simple," and recommends that the MIB working
group take as its starting inputs the MIB definitions found in the
High-Level Entity Management Systems (HEMS) RFC1024 [9], the initial
SNMP specification [10], and the CMIS/CMIP memos [11,12].
Thus, the list of managed objects defined here, has been derived by
taking only those elements which are considered essential. Since
such elements are essential, there is no need to allow the
implementation of individual objects, to be optional. Rather, all
compliant implementations will contain all applicable (see below)
objects defined in this memo.
This approach of taking only the essential objects is NOT
restrictive, since the SMI defined in the companion memo provides
three extensibility mechanisms: one, the addition of new standard
objects through the definitions of new versions of the MIB; two, the
addition of widely-available but non-standard objects through the
multilateral subtree; and three, the addition of private objects
through the enterprises subtree. Such additional objects can not only
be used for vendor-specific elements, but also for experimentation as
required to further the knowledge of which other objects are
essential.
The primary criterion for being considered essential was for an
object to be contained in all of the above referenced MIB
definitions. A few other objects have been included, but only if the
MIB working group believed they are truly essential. The detailed
list of criteria against which potential inclusions in this (initial)
MIB were considered, was:
1) An object needed to be essential for either fault or
configuration management.
2) Only weak control objects were permitted (by weak, it
is meant that tampering with them can do only limited
damage). This criterion reflects the fact that the
current management protocols are not sufficiently secure
to do more powerful control operations.
3) Evidence of current use and utility was required.
4) An attempt was made to limit the number of objects to
about 100 to make it easier for vendors to fully
instrument their software.
5) To avoid redundant variables, it was required that no
object be included that can be derived from others in the
MIB.
6) Implementation specific objects (e.g., for BSD UNIX)
were excluded.
7) It was agreed to avoid heavily instrumenting critical
sections of code. The general guideline was one counter
per critical section per layer.
4. Objects
Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. Objects in the MIB are
defined using Abstract Syntax Notation One (ASN.1) [13].
The mechanisms used for describing these objects are specified in the
companion memo. In particular, each object has a name, a syntax, and
an encoding. The name is an object identifier, an administratively
assigned name, which specifies an object type. The object type
together with an object instance serves to uniquely identify a
specific instantiation of the object. For human convenience, we
often use a textual string, termed the OBJECT DESCRIPTOR, to also
refer to the object type.
The syntax of an object type defines the abstract data structure
corresponding to that object type. The ASN.1 language is used for
this purpose. However, the companion memo purposely restricts the
ASN.1 constructs which may be used. These restrictions are
explicitly made for simplicity.
The encoding of an object type is simply how that object type is
represented using the object type's syntax. Implicitly tied to the
notion of an object type's syntax and encoding is how the object type
is represented when being transmitted on the network. This memo
specifies the use of the basic encoding rules of ASN.1 [14].
4.1. Object Groups
Since this list of managed objects contains only the essential
elements, there is no need to allow individual objects to be
optional. Rather, the objects are arranged into the following
groups:
- System
- Interfaces
- Address Translation
- IP
- ICMP
- TCP
- UDP
- EGP
There are two reasons for defining these groups: one, to provide a
means of assigning object identifiers; two, to provide a method for
implementations of managed agents to know which objects they must
implement. This method is as follows: if the semantics of a group is
applicable to an implementation, then it must implement all objects
in that group. For example, an implementation must implement the EGP
group if and only if it implements the EGP protocol.
4.2. Format of Definitions
The next section contains the specification of all object types
contained in the MIB. Following the conventions of the companion
memo, the object types are defined using the following fields:
OBJECT:
-------
A textual name, termed the OBJECT DESCRIPTOR, for the
object type, along with its corresponding OBJECT
IDENTIFIER.
Syntax:
The abstract syntax for the object type, presented using
ASN.1. This must resolve to an instance of the ASN.1
type ObjectSyntax defined in the SMI.
Definition:
A textual description of the semantics of the object
type. Implementations should ensure that their
interpretation of the object type fulfills this
definition since this MIB is intended for use in multi-
vendor environments. As such it is vital that object
types have consistent meaning across all machines.
Access:
One of read-only, read-write, write-only, or
not-accessible.
Status:
One of mandatory, optional, or obsolete.
5. Object Definitions
RFC1156-MIB
DEFINITIONS ::= BEGIN
IMPORTS
mgmt, OBJECT-TYPE, NetworkAddress, IpAddress,
Counter, Gauge, TimeTicks
FROM RFC1155-SMI;
mib OBJECT IDENTIFIER ::= { mgmt 1 }
system OBJECT IDENTIFIER ::= { mib 1 }
interfaces OBJECT IDENTIFIER ::= { mib 2 }
at OBJECT IDENTIFIER ::= { mib 3 }
ip OBJECT IDENTIFIER ::= { mib 4 }
icmp OBJECT IDENTIFIER ::= { mib 5 }
tcp OBJECT IDENTIFIER ::= { mib 6 }
udp OBJECT IDENTIFIER ::= { mib 7 }
egp OBJECT IDENTIFIER ::= { mib 8 }
END
5.1. The System Group
Implementation of the System group is mandatory for all
systems.
OBJECT:
-------
sysDescr { system 1 }
Syntax:
OCTET STRING
Definition:
A textual description of the entity. This value should
include the full name and version identification of the
system's hardware type, software operating-system, and
networking software. It is mandatory that this only
contain printable ASCII characters.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
sysObjectID { system 2 }
Syntax:
OBJECT IDENTIFIER
Definition:
The vendor's authoritative identification of the network
management subsystem contained in the entity. This value
is allocated within the SMI enterprises subtree
(1.3.6.1.4.1) and provides an easy and unambiguous means
for determining "what kind of box" is being managed. For
example, if vendor "Flintstones, Inc." was assigned the
subtree 1.3.6.1.4.1.42, it could assign the identifier
1.3.6.1.4.1.42.1.1 to its "Fred Router".
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
sysUpTime { system 3 }
Syntax:
TimeTicks
Definition:
The time (in hundredths of a second) since the network
management portion of the system was last re-initialized.
Access:
read-only.
Status:
mandatory.
5.2. The Interfaces Group
Implementation of the Interfaces group is mandatory for all
systems.
OBJECT:
-------
ifNumber { interfaces 1 }
Syntax:
INTEGER
Definition:
The number of network interfaces (regardless of their
current state) on which this system can send/receive IP
datagrams.
Access:
read-only.
Status:
mandatory.
5.2.1. The Interfaces Table
OBJECT:
-------
ifTable { interfaces 2 }
Syntax:
SEQUENCE OF IfEntry
Definition:
A list of interface entries. The number of entries is
given by the value of ifNumber.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ifEntry { ifTable 1 }
Syntax:
IfEntry ::= SEQUENCE {
ifIndex
INTEGER,
ifDescr
OCTET STRING,
ifType
INTEGER,
ifMtu
INTEGER,
ifSpeed
Gauge,
ifPhysAddress
OCTET STRING,
ifAdminStatus
INTEGER,
ifOperStatus
INTEGER,
ifLastChange
TimeTicks,
ifInOctets
Counter,
ifInUcastPkts
Counter,
ifInNUcastPkts
Counter,
ifInDiscards
Counter,
ifInErrors
Counter,
ifInUnknownProtos
Counter,
ifOutOctets
Counter,
ifOutUcastPkts
Counter,
ifOutNUcastPkts
Counter,
ifOutDiscards
Counter,
ifOutErrors
Counter,
ifOutQLen
Gauge
}
Definition:
An interface entry containing objects at the subnetwork
layer and below for a particular interface.
Access:
read-write.
Status:
mandatory.
We now consider the individual components of each interface
entry:
OBJECT:
-------
ifIndex { ifEntry 1 }
Syntax:
INTEGER
Definition:
A unique value for each interface. Its value ranges
between 1 and the value of ifNumber. The value for each
interface must remain constant at least from one re-
initialization of the entity's network management system
to the next re-initialization.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifDescr { ifEntry 2 }
Syntax:
OCTET STRING
Definition:
A text string containing information about the interface.
This string should include the name of the manufacturer,
the product name and the version of the hardware
interface. The string is intended for presentation to a
human; it must not contain anything but printable ASCII
characters.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifType { ifEntry 3 }
Syntax:
INTEGER {
other(1), -- none of the following
regular1822(2),
hdh1822(3),
ddn-x25(4),
rfc877-x25(5),
ethernet-csmacd(6),
iso88023-csmacd(7),
iso88024-tokenBus(8),
iso88025-tokenRing(9),
iso88026-man(10),
starLan(11),
proteon-10MBit(12),
proteon-80MBit(13),
hyperchannel(14),
fddi(15),
lapb(16),
sdlc(17),
t1-carrier(18),
cept(19), -- european equivalent of T-1
basicIsdn(20),
primaryIsdn(21),
-- proprietary serial
propPointToPointSerial(22)
}
Definition:
The type of interface, distinguished according to the
physical/link/network protocol(s) immediately "below" IP
in the protocol stack.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifMtu { ifEntry 4 }
Syntax:
INTEGER
Definition:
The size of the largest IP datagram which can be
sent/received on the interface, specified in octets.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifSpeed { ifEntry 5 }
Syntax:
Gauge
Definition:
An estimate of the interface's current bandwidth in bits
per second. For interfaces which do not vary in
bandwidth or for those where no accurate estimation can
be made, this object should contain the nominal
bandwidth.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifPhysAddress { ifEntry 6 }
Syntax:
OCTET STRING
Definition:
The interface's address at the protocol layer immediately
"below" IP in the protocol stack. For interfaces which
do not have such an address (e.g., a serial line), this
object should contain an octet string of zero length.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifAdminStatus { ifEntry 7 }
Syntax:
INTEGER {
up(1), -- ready to pass packets
down(2),
testing(3) -- in some test mode
}
Definition:
The desired state of the interface. The testing(3) state
indicates that no operational packets can be passed.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ifOperStatus { ifEntry 8 }
Syntax:
INTEGER {
up(1), -- ready to pass packets
down(2),
testing(3) -- in some test mode
}
Definition:
The current operational state of the interface. The
testing(3) state indicates that no operational packets
can be passed.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifLastChange { ifEntry 9 }
Syntax:
TimeTicks
Definition:
The value of sysUpTime at the time the interface entered
its current operational state. If the current state was
entered prior to the last re-initialization of the local
network management subsystem, then this object contains a
zero value.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInOctets { ifEntry 10 }
Syntax:
Counter
Definition:
The total number of octets received on the interface,
including framing characters.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInUcastPkts { ifEntry 11 }
Syntax:
Counter
Definition:
The number of (subnet) unicast packets delivered to a
higher-layer protocol.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInNUcastPkts { ifEntry 12 }
Syntax:
Counter
Definition:
The number of non-unicast (i.e., subnet broadcast or
subnet multicast) packets delivered to a higher-layer
protocol.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInDiscards { ifEntry 13 }
Syntax:
Counter
Definition:
The number of inbound packets which were chosen to be
discarded even though no errors had been detected to
prevent their being deliverable to a higher-layer
protocol. One possible reason for discarding such a
packet could be to free up buffer space.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInErrors { ifEntry 14 }
Syntax:
Counter
Definition:
The number of inbound packets that contained errors
preventing them from being deliverable to a higher-layer
protocol.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInUnknownProtos { ifEntry 15 }
Syntax:
Counter
Definition:
The number of packets received via the interface which
were discarded because of an unknown or unsupported
protocol.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutOctets { ifEntry 16 }
Syntax:
Counter
Definition:
The total number of octets transmitted out of the
interface, including framing characters.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutUcastPkts { ifEntry 17 }
Syntax:
Counter
Definition:
The total number of packets that higher-level protocols
requested be transmitted to a subnet-unicast address,
including those that were discarded or not sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutNUcastPkts { ifEntry 18 }
Syntax:
Counter
Definition:
The total number of packets that higher-level protocols
requested be transmitted to a non-unicast (i.e., a subnet
broadcast or subnet multicast) address, including those
that were discarded or not sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutDiscards { ifEntry 19 }
Syntax:
Counter
Definition:
The number of outbound packets which were chosen to be
discarded even though no errors had been detected to
prevent their being transmitted. One possible reason for
discarding such a packet could be to free up buffer
space.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutErrors { ifEntry 20 }
Syntax:
Counter
Definition:
The number of outbound packets that could not be
transmitted because of errors.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutQLen { ifEntry 21 }
Syntax:
Gauge
Definition:
The length of the output packet queue (in packets).
Access:
read-only.
Status:
mandatory.
5.3. The Address Translation Group
Implementation of the Address Translation group is mandatory
for all systems.
The Address Translation group contains one table which is the
union across all interfaces of the translation tables for
converting a NetworkAddress (e.g., an IP address) into a
subnetwork-specific address. For lack of a better term, this
document refers to such a subnetwork-specific address as a
"physical" address.
Examples of such translation tables are: for broadcast media
where ARP is in use, the translation table is equivalent to
the ARP cache; or, on an X.25 network where non-algorithmic
translation to X.121 addresses is required, the translation
table contains the NetworkAddress to X.121 address
equivalences.
OBJECT:
-------
atTable { at 1 }
Syntax:
SEQUENCE OF AtEntry
Definition:
The Address Translation tables contain the NetworkAddress
to "physical" address equivalences. Some interfaces do
not use translation tables for determining address
equivalences (e.g., DDN-X.25 has an algorithmic method);
if all interfaces are of this type, then the Address
Translation table is empty, i.e., has zero entries.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
atEntry { atTable 1 }
Syntax:
AtEntry ::= SEQUENCE {
atIfIndex
INTEGER,
atPhysAddress
OCTET STRING,
atNetAddress
NetworkAddress
}
Definition:
Each entry contains one NetworkAddress to "physical"
address equivalence.
Access:
read-write.
Status:
mandatory.
We now consider the individual components of each Address
Translation table entry:
OBJECT:
-------
atIfIndex { atEntry 1 }
Syntax:
INTEGER
Definition:
The interface on which this entry's equivalence is
effective. The interface identified by a particular
value of this index is the same interface as identified
by the same value of ifIndex.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
atPhysAddress { atEntry 2 }
Syntax:
OCTET STRING
Definition:
The media-dependent "physical" address.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
atNetAddress { atEntry 3 }
Syntax:
NetworkAddress
Definition:
The NetworkAddress (e.g., the IP address) corresponding to
the media-dependent "physical" address.
Access:
read-write.
Status:
mandatory.
5.4. The IP Group
Implementation of the IP group is mandatory for all systems.
OBJECT:
-------
ipForwarding { ip 1 }
Syntax:
INTEGER {
gateway(1), -- entity forwards datagrams
host(2) -- entity does NOT forward datagrams
}
Definition:
The indication of whether this entity is acting as an IP
gateway in respect to the forwarding of datagrams
received by, but not addressed to, this entity. IP
gateways forward datagrams; Hosts do not (except those
Source-Routed via the host).
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipDefaultTTL { ip 2 }
Syntax:
INTEGER
Definition:
The default value inserted into the Time-To-Live field of
the IP header of datagrams originated at this entity,
whenever a TTL value is not supplied by the transport
layer protocol.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipInReceives { ip 3 }
Syntax:
Counter
Definition:
The total number of input datagrams received from
interfaces, including those received in error.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipInHdrErrors { ip 4 }
Syntax:
Counter
Definition:
The number of input datagrams discarded due to errors in
their IP headers, including bad checksums, version number
mismatch, other format errors, time-to-live exceeded,
errors discovered in processing their IP options, etc.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipInAddrErrors { ip 5 }
Syntax:
Counter
Definition:
The number of input datagrams discarded because the IP
address in their IP header's destination field was not a
valid address to be received at this entity. This count
includes invalid addresses (e.g., 0.0.0.0) and addresses
of unsupported Classes (e.g., Class E). For entities
which are not IP Gateways and therefore do not forward
datagrams, this counter includes datagrams discarded
because the destination address was not a local address.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipForwDatagrams { ip 6 }
Syntax:
Counter
Definition:
The number of input datagrams for which this entity was
not their final IP destination, as a result of which an
attempt was made to find a route to forward them to that
final destination. In entities which do not act as IP
Gateways, this counter will include only those packets
which were Source-Routed via this entity, and the
Source-Route option processing was successful.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipInUnknownProtos { ip 7 }
Syntax:
Counter
Definition:
The number of locally-addressed datagrams received
successfully but discarded because of an unknown or
unsupported protocol.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipInDiscards { ip 8 }
Syntax:
Counter
Definition:
The number of input IP datagrams for which no problems
were encountered to prevent their continued processing,
but which were discarded (e.g. for lack of buffer space).
Note that this counter does not include any datagrams
discarded while awaiting re-assembly.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipInDelivers { ip 9 }
Syntax:
Counter
Definition:
The total number of input datagrams successfully
delivered to IP user-protocols (including ICMP).
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipOutRequests { ip 10 }
Syntax:
Counter
Definition:
The total number of IP datagrams which local IP user-
protocols (including ICMP) supplied to IP in requests for
transmission. Note that this counter does not include
any datagrams counted in ipForwDatagrams.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipOutDiscards { ip 11 }
Syntax:
Counter
Definition:
The number of output IP datagrams for which no problem
was encountered to prevent their transmission to their
destination, but which were discarded (e.g., for lack of
buffer space). Note that this counter would include
datagrams counted in ipForwDatagrams if any such packets
met this (discretionary) discard criterion.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipOutNoRoutes { ip 12 }
Syntax:
Counter
Definition:
The number of IP datagrams discarded because no route
could be found to transmit them to their destination.
Note that this counter includes any packets counted in
ipForwDatagrams which meet this "no-route" criterion.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipReasmTimeout { ip 13 }
Syntax:
INTEGER
Definition:
The maximum number of seconds which received fragments
are held while they are awaiting reassembly at this
entity.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipReasmReqds { ip 14 }
Syntax:
Counter
Definition:
The number of IP fragments received which needed to be
reassembled at this entity.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipReasmOKs { ip 15 }
Syntax:
Counter
Definition:
The number of IP datagrams successfully re-assembled.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipReasmFails { ip 16 }
Syntax:
Counter
Definition:
The number of failures detected by the IP re-assembly
algorithm (for whatever reason: timed out, errors, etc).
Note that this is not necessarily a count of discarded IP
fragments since some algorithms (notably RFC815's) can
lose track of the number of fragments by combining them
as they are received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipFragOKs { ip 17 }
Syntax:
Counter
Definition:
The number of IP datagrams that have been successfully
fragmented at this entity.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipFragFails { ip 18 }
Syntax:
Counter
Definition:
The number of IP datagrams that have been discarded
because they needed to be fragmented at this entity but
could not be, e.g., because their "Don't Fragment" flag
was set.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipFragCreates { ip 19 }
Syntax:
Counter
Definition:
The number of IP datagram fragments that have been
generated as a result of fragmentation at this entity.
Access:
read-only.
Status:
mandatory.
5.4.1. The IP Address Table
The Ip Address table contains this entity's IP addressing
information.
OBJECT:
-------
ipAddrTable { ip 20 }
Syntax:
SEQUENCE OF IpAddrEntry
Definition:
The table of addressing information relevant to this
entity's IP addresses.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipAddrEntry { ipAddrTable 1 }
Syntax:
IpAddrEntry ::= SEQUENCE {
ipAdEntAddr
IpAddress,
ipAdEntIfIndex
INTEGER,
ipAdEntNetMask
IpAddress,
ipAdEntBcastAddr
INTEGER
}
Definition:
The addressing information for one of this entity's IP
addresses.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipAdEntAddr { ipAddrEntry 1 }
Syntax:
IpAddress
Definition:
The IP address to which this entry's addressing
information pertains.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipAdEntIfIndex { ipAddrEntry 2 }
Syntax:
INTEGER
Definition:
The index value which uniquely identifies the interface
to which this entry is applicable. The interface
identified by a particular value of this index is the
same interface as identified by the same value of
ifIndex.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipAdEntNetMask { ipAddrEntry 3 }
Syntax:
IpAddress
Definition:
The subnet mask associated with the IP address of this
entry. The value of the mask is an IP address with all
the network bits set to 1 and all the hosts bits set to
0.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipAdEntBcastAddr { ipAddrEntry 4 }
Syntax:
INTEGER
Definition:
The value of the least-significant bit in the IP
broadcast address used for sending datagrams on the
(logical) interface associated with the IP address of
this entry. For example, when the Internet standard
all-ones broadcast address is used, the value will be 1.
Access:
read-only.
Status:
mandatory.
5.4.2. The IP Routing Table
The IP Routing Table contains an entry for each route
presently known to this entity. Note that the action to be
taken in response to a request to read a non-existent entry,
is specific to the network management protocol being used.
OBJECT:
-------
ipRoutingTable { ip 21 }
Syntax:
SEQUENCE OF IpRouteEntry
Definition:
This entity's IP Routing table.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipRouteEntry { ipRoutingTable 1 }
Syntax:
IpRouteEntry ::= SEQUENCE {
ipRouteDest
IpAddress,
ipRouteIfIndex
INTEGER,
ipRouteMetric1
INTEGER,
ipRouteMetric2
INTEGER,
ipRouteMetric3
INTEGER,
ipRouteMetric4
INTEGER,
ipRouteNextHop
IpAddress,
ipRouteType
INTEGER,
ipRouteProto
INTEGER,
ipRouteAge
INTEGER
}
Definition:
A route to a particular destination.
Access:
read-write.
Status:
mandatory.
We now consider the individual components of each route in the
IP Routing Table:
OBJECT:
-------
ipRouteDest { ipRouteEntry 1 }
Syntax:
IpAddress
Definition:
The destination IP address of this route. An entry with
a value of 0.0.0.0 is considered a default route.
Multiple such default routes can appear in the table, but
access to such multiple entries is dependent on the
table-access mechanisms defined by the network management
protocol in use.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipRouteIfIndex { ipRouteEntry 2 }
Syntax:
INTEGER
Definition:
The index value which uniquely identifies the local
interface through which the next hop of this route should
be reached. The interface identified by a particular
value of this index is the same interface as identified
by the same value of ifIndex.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipRouteMetric1 { ipRouteEntry 3 }
Syntax:
INTEGER
Definition:
The primary routing metric for this route. The semantics
of this metric are determined by the routing-protocol
specified in the route's ipRouteProto value. If this
metric is not used, its value should be set to -1.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipRouteMetric2 { ipRouteEntry 4 }
Syntax:
INTEGER
Definition:
An alternate routing metric for this route. The
semantics of this metric are determined by the routing-
protocol specified in the route's ipRouteProto value. If
this metric is not used, its value should be set to -1.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipRouteMetric3 { ipRouteEntry 5 }
Syntax:
INTEGER
Definition:
An alternate routing metric for this route. The
semantics of this metric are determined by the routing-
protocol specified in the route's ipRouteProto value. If
this metric is not used, its value should be set to -1.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipRouteMetric4 { ipRouteEntry 6 }
Syntax:
INTEGER
Definition:
An alternate routing metric for this route. The
semantics of this metric are determined by the routing-
protocol specified in the route's ipRouteProto value. If
this metric is not used, its value should be set to -1.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipRouteNextHop { ipRouteEntry 7 }
Syntax:
IpAddress
Definition:
The IP address of the next hop of this route.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipRouteType { ipRouteEntry 8 }
Syntax:
INTEGER {
other(1), -- none of the following
invalid(2), -- an invalidated route
-- route to directly
direct(3), -- connected (sub-)network
-- route to a non-local
remote(4), -- host/network/sub-network
}
Definition:
The type of route.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ipRouteProto { ipRouteEntry 9 }
Syntax:
INTEGER {
other(1), -- none of the following
-- non-protocol information,
-- e.g., manually configured
local(2), -- entries
-- set via a network management
netmgmt(3), -- protocol
-- obtained via ICMP,
icmp(4), -- e.g., Redirect
-- the remaining values are
-- all gateway routing protocols
egp(5),
ggp(6),
hello(7),
rip(8),
is-is(9),
es-is(10),
ciscoIgrp(11),
bbnSpfIgp(12),
oigp(13)
}
Definition:
The routing mechanism via which this route was learned.
Inclusion of values for gateway routing protocols is not
intended to imply that hosts should support those
protocols.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ipRouteAge { ipRouteEntry 10 }
Syntax:
INTEGER
Definition:
The number of seconds since this route was last updated
or otherwise determined to be correct. Note that no
semantics of "too old" can be implied except through
knowledge of the routing protocol by which the route was
learned.
Access:
read-write.
Status:
mandatory.
5.5. The ICMP Group
Implementation of the ICMP group is mandatory for all systems.
The ICMP group contains the ICMP input and output statistics.
Note that individual counters for ICMP message (sub-)codes have been
omitted from this (version of the) MIB for simplicity.
OBJECT:
-------
icmpInMsgs { icmp 1 }
Syntax:
Counter
Definition:
The total number of ICMP messages which the entity
received. Note that this counter includes all those
counted by icmpInErrors.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInErrors { icmp 2 }
Syntax:
Counter
Definition:
The number of ICMP messages which the entity received but
determined as having errors (bad ICMP checksums, bad
length, etc.).
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInDestUnreachs { icmp 3 }
Syntax:
Counter
Definition:
The number of ICMP Destination Unreachable messages
received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInTimeExcds { icmp 4 }
Syntax:
Counter
Definition:
The number of ICMP Time Exceeded messages received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInParmProbs { icmp 5 }
Syntax:
Counter
Definition:
The number of ICMP Parameter Problem messages received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInSrcQuenchs { icmp 6 }
Syntax:
Counter
Definition:
The number of ICMP Source Quench messages received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInRedirects { icmp 7 }
Syntax:
Counter
Definition:
The number of ICMP Redirect messages received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInEchos { icmp 8 }
Syntax:
Counter
Definition:
The number of ICMP Echo (request) messages received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInEchoReps { icmp 9 }
Syntax:
Counter
Definition:
The number of ICMP Echo Reply messages received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInTimestamps { icmp 10 }
Syntax:
Counter
Definition:
The number of ICMP Timestamp (request) messages received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInTimestampReps { icmp 11 }
Syntax:
Counter
Definition:
The number of ICMP Timestamp Reply messages received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInAddrMasks { icmp 12 }
Syntax:
Counter
Definition:
The number of ICMP Address Mask Request messages
received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpInAddrMaskReps { icmp 13 }
Syntax:
Counter
Definition:
The number of ICMP Address Mask Reply messages received.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutMsgs { icmp 14 }
Syntax:
Counter
Definition:
The total number of ICMP messages which this entity
attempted to send. Note that this counter includes all
those counted by icmpOutErrors.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutErrors { icmp 15 }
Syntax:
Counter
Definition:
The number of ICMP messages which this entity did not
send due to problems discovered within ICMP such as a
lack of buffers. This value should not include errors
discovered outside the ICMP layer such as the inability
of IP to route the resultant datagram. In some
implementations there may be no types of error which
contribute to this counter's value.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutDestUnreachs { icmp 16 }
Syntax:
Counter
Definition:
The number of ICMP Destination Unreachable messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutTimeExcds { icmp 17 }
Syntax:
Counter
Definition:
The number of ICMP Time Exceeded messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutParmProbs { icmp 18 }
Syntax:
Counter
Definition:
The number of ICMP Parameter Problem messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutSrcQuenchs { icmp 19 }
Syntax:
Counter
Definition:
The number of ICMP Source Quench messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutRedirects { icmp 20 }
Syntax:
Counter
Definition:
The number of ICMP Redirect messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutEchos { icmp 21 }
Syntax:
Counter
Definition:
The number of ICMP Echo (request) messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutEchoReps { icmp 22 }
Syntax:
Counter
Definition:
The number of ICMP Echo Reply messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutTimestamps { icmp 23 }
Syntax:
Counter
Definition:
The number of ICMP Timestamp (request) messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutTimestampReps { icmp 24 }
Syntax:
Counter
Definition:
The number of ICMP Timestamp Reply messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutAddrMasks { icmp 25 }
Syntax:
Counter
Definition:
The number of ICMP Address Mask Request messages sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
icmpOutAddrMaskReps { icmp 26 }
Syntax:
Counter
Definition:
The number of ICMP Address Mask Reply messages sent.
Access:
read-only.
Status:
mandatory.
5.6. The TCP Group
Implementation of the TCP group is mandatory for all systems
that implement the TCP protocol.
Note that instances of object types that represent information
about a particular TCP connection are transient; they persist
only as long as the connection in question.